The Treaty of Tordesillas, signed in Tordesillas, Spain on 7 June 1494, and authenticated in Setbal, Portugal, divided the newly discovered lands outside Europe between the Portuguese Empire and the Spanish Empire (Crown of Castile), along a meridian 370 leagues west of the Cape Verde islands, off the west coast of Africa. That line of demarcation was about halfway between the Cape Verde islands (already Portuguese) and the islands entered by Christopher Columbus on his first voyage (claimed for Castile and Len), named in the treaty as Cipangu and Antillia (Cuba and Hispaniola).

The lands to the east would belong to Portugal and the lands to the west to Castile, modifying an earlier division proposed by Pope Alexander VI. The treaty was signed by Spain, 2 July 1494, and by Portugal, 5 September 1494. The other side of the world was divided a few decades later by the Treaty of Zaragoza, signed on 22 April 1529, which specified the antimeridian to the line of demarcation specified in the Treaty of Tordesillas. Originals of both treaties are kept at the General Archive of the Indies in Spain and at the Torre do Tombo National Archive in Portugal.Despite considerable lack of information regarding the geography of the New World, Portugal and Spain largely respected the treaty. The other European powers however did not sign the treaty and generally ignored it, particularly those that became Protestant after the Reformation. Similarly, the indigenous peoples of the Americas did not acknowledge the treaty, and as the legal foundation for the discovery doctrine, it has been a source of ongoing tension regarding land ownership into modern times, cited as recently as the 2005 United States Supreme Court case Sherrill v. Oneida Nation.

The treaty was included by UNESCO in 2007 in its Memory of the World Programme.

Pedro Álvares Cabral (European Portuguese: [ˈpeðɾu ˈaɫvɐr(ɨ)ʃ kɐˈβɾaɫ] or Brazilian Portuguese: [ˈpedɾu ˈawvɐɾis kaˈbɾaw]; born Pedro Álvares de Gouveia; c. 1467 or 1468 – c. 1520) was a Portuguese nobleman, military commander, navigator and explorer regarded as the European discoverer of Brazil. In 1500, Cabral conducted the first substantial exploration of the northeast coast of South America and claimed it for Portugal. While details of Cabral's early life remain unclear, it is known that he came from a minor noble family and received a good education. He was appointed to head an expedition to India in 1500, following Vasco da Gama's newly-opened route around Africa. The undertaking had the aim of returning with valuable spices and of establishing trade relations in India—bypassing the monopoly on the spice trade then in the hands of Arab, Turkish and Italian merchants. Although the previous expedition of Vasco da Gama to India, on its sea route, had recorded signs of land west of the southern Atlantic Ocean (in 1497), Cabral led the first known expedition to have touched four continents: Europe, Africa, America, and Asia.His fleet of 13 ships sailed far into the western Atlantic Ocean, perhaps intentionally, and made landfall (April 1500) on what he initially assumed to be a large island. As the new land was within the Portuguese sphere according to the 1494 Treaty of Tordesillas, Cabral claimed it for the Portuguese Crown. He explored the coast, realizing that the large land mass was probably a continent, and dispatched a ship to notify King Manuel I of the new territory. The continent was South America, and the land he had claimed for Portugal later came to be known as Brazil. The fleet reprovisioned and then turned eastward to resume the journey to India.

A storm in the southern Atlantic caused the loss of several ships, and the six remaining ships eventually rendezvoused in the Mozambique Channel before proceeding to Calicut in India. Cabral was originally successful in negotiating trading rights, but Arab merchants saw Portugal's venture as a threat to their monopoly and stirred up an attack by both Muslims and Hindus on the Portuguese entrepôt. The Portuguese sustained many casualties and their facilities were destroyed. Cabral took vengeance by looting and burning the Arab fleet and then bombarded the city in retaliation for its ruler having failed to explain the unexpected attack. From Calicut the expedition sailed to the Kingdom of Cochin, another Indian city-state, where Cabral befriended its ruler and loaded his ships with coveted spices before returning to Europe. Despite the loss of human lives and ships, Cabral's voyage was deemed a success upon his return to Portugal. The extraordinary profits resulting from the sale of the spices bolstered the Portuguese Crown's finances and helped lay the foundation of a Portuguese Empire that would stretch from the Americas to the Far East.Cabral was later passed over, possibly as a result of a quarrel with Manuel I, when a new fleet was assembled to establish a more robust presence in India. Having lost favor with the King, he retired to a private life of which few records survive. His accomplishments slipped mostly into obscurity for more than 300 years. Decades after Brazil's independence from Portugal in the 19th century, Cabral's reputation began to be rehabilitated by Emperor Pedro II of Brazil. Historians have long argued whether Cabral was Brazil's discoverer, and whether the discovery was accidental or intentional. The first question has been settled by the observation that the few, cursory encounters by explorers before him were barely noticed at the time and contributed nothing to the future development and history of the land which would become Brazil, the sole Portuguese-speaking nation in the Americas. On the second question, no definite consensus has been formed, and the intentional discovery hypothesis lacks solid proof. Nevertheless, although he was overshadowed by contemporary explorers, historians consider Cabral to be a major figure of the Age of Discovery.